Various techniques are known to multiply a current. A current multiplier generates a current at an output that is higher than the current supplied by the power supply. Since power is conserved, an increased current output results in an output voltage that is lower than the input voltage.
Some current multipliers use a pulsed switching technique controlled by an oscillator, where large filters are used to convert a pulsed waveform into a DC current. Such pulsed multipliers generate electromagnetic interference (EMI) and other electrical noise and are relatively large. One such multiplier is a switch-mode DC-DC converter. In some situations, a substantially noiseless converter is required, precluding the use of a switch-mode converter.
A CUK converter is a special topology of DC/DC converter which uses inductive and capacitive energy transfer to generate an output current, with the advantage of low ripple current at the input when supplying a constant load current at the output. For a simple CUK converter, two inductors, a large coupling capacitor, an output filter capacitor, a switch transistor, a diode, and its control circuit are needed. The coupling capacitor must be relatively large for medium and high load currents.
In one example of the need for a current multiplier, a high brightness light emitting diode (LED) only needs a small voltage (e.g., 3.4 volts) but a fairly high current. If the power source is a 12 volt car battery, a converter is used to supply the required current through the LED at 3.4 volts. An idealized converter will thus multiply the current drawn from the battery by 12/3.4. However, known converters generate noise (e.g., a switching converter) or require large coupling capacitors (e.g., CUK converter).
What is needed is a direct current multiplier that is simple, small, and does not generate substantial noise to both the power supply and the load.